In known work apparatus, the fan cover is releasably attached outside to the housing, for example, by means of screws so that the fan cover can be removed as required. On the inner side of the fan cover, an air-conducting wall is provided which is separate from the fan cover but is releasably connected thereto. This air-conducting wall extends into an axial collar which surrounds the fan wheel. The fan cover and the air-conducting wall having the axial collar are separate parts which are connected to each other by an insert connection and are tightly connected to each other with screws in order to avoid a loosening of the air-conducting wall as a consequence of engine vibrations or for other reasons. The fan cover and the air-conducting wall can then be removed together from the motor fan unit by releasing the attachment screws of the fan cover. A tight quiet seating of the air-conducting sheet metal in the fan cover is assured by the above-described connection between fan cover and air-conducting wall.
The known arrangement has a complex configuration since the fan cover and the air-conducting wall must be produced as separate parts and must be assembled to form one part while utilizing latching tongues and screws in order to avoid a loosening of the air-conducting wall under the vibration loads of the motor.